It is well known in motor vehicles to provide a combination lap-shoulder seat belt assembly including a shoulder belt extending at a vertical angle across the torso of an occupant and joining a lap belt which extends generally horizontally across the lap of the occupant. A junction of the shoulder belt and the lap belt typically carries a latch plate assembly which is releasably connected to a buckle assembly anchored to the vehicle.
It is occasionally necessary to provide an extender seat belt assembly to accommodate an occupant of enlarged proportions or one who is significantly greater than the 95th percentile weight anthropometry. It is typical to provide a length of extender webbing with an extender buckle assembly at one end for attachment to the original latch plate assembly and an extender latch plate assembly at the other end for connection with the original buckle assembly. This provides a lap belt extender for accommodating the occupant.
Typically, the length of extender webbing for the lap belt extender is non-adjustable and customized such that each occupant must be measured to determine the needed length of extender webbing. This has the disadvantage of requiring time for a customized extender to be made.
It is also known that extenders should be easy to remove and install, since they should only be used by the intended vehicle occupant.
Extending the lap belt to accommodate the occupant necessarily alters the position of the junction of the shoulder belt and the lap belt of the lap-shoulder belt assembly from the side of the occupant at the buckle assembly towards the center of the occupant. This has the effect of altering the vertical angle of the shoulder belt relative the lap belt to a more vertical angle.